Work-table mechanisms for blind-stitch machines



Sept. 27, 1955 F. PARRY 8,862

WORK-TABLE MECHANISMS FOR BLIND-STITCH MACHlENES Filed June 7, 1952 4Sheets-Sheet l [N VEN TOR (9; (170k 77129 WITNESS BY W Yu fi I MATTORNEY F. PARRY Sept. 27, 1955 WORK-TABLE MECHANISMS FOR BLIND-STITCHMACHINES 4 Sheets-Sheet 2 Filed June 7, 1952 INVENTOR 011016 Jam/3 BYATTORNEY Sept. 27, 1955 F. PARRY 2,718,362

WORK-TABLE MECHANISMS FOR BLIND-STITCH MACHINES Filed June 7, 1952 4Sheets-Sheet 3 FEE" IIM

(991mg Ja 1:9 WITNES BY I A RNE Sept. 27, 1955 F. PARRY WORK-TABLEMECHANISMS FOR BLIND-STITCH MACHINES 4 Sheets-Sheet 4 Filed June 7, 1952INVENTOR c9;cm Jam/ 9 ATTORNEY WITNESS 2,718,862 Patented Sept. 27, 1955lVORK-TABLE MECHANISMS FOR BLIND-STITCH MACHINES Frank Parry, Trumbull,Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. 1., acorporation of New Jersey Application June 7, 1952, Serial No. 292,264

12 Claims. (Cl. 112-260) This invention relates to blind-stitch sewingmachines and more particularly to an improvement in the supportingstructure of the work-table, whereby the latter can be accurately raisedand lowered to accommodate the machine to materials of differentthicknesses, and also to position the work-table accurately with respectto the presser-foot and stitch-forming mechanism so that true blindstitches can be made with a minimum of stitchexposure on the outer faceof the material.

It is an object of the present invention to provide an improvedwork-table mechanism having provision for micrometer adjustment of thenormal elevation of the work-table.

Another object of the invention is to provide a worktable elevationregulating means having a conveniently located manually operableadjusting element supported on a detachable cover, the removal of whichwill expose the regulating means for adjustment, repair or replacement.

Still another object of the invention is to provide a work-tableelevation regulating means which is effective bodily to elevate thework-table relative to the presserfoot as opposed to pivotally elevatingthe work-table about a fixed axis as is common in previous machines.

With these and other objects in view, which will more fully appear, thenature of the invention will be more clearly understood by following thedescription, the appended claims, and the several views illustrated inthe accompanying drawings.

In the drawings:

Fig. 1 is a top plan view of a machine constructed in accordance with myinvention, the bed cover-plate being removed and certain of the partsbeing in section better to illustrate the details of the machine.

Fig. 2 represents a vertical sectional view taken substantially alongthe line 22, Fig. l.

Fig. 3 represents an enlarged horizontal sectional view takensubstantially along the line 33, Fig. 2, showing the adjustable stop fordetermining the normal elevated operating position of the work-table anda portion of the spring-biased linkage utilized for maintaining thework-table in contact with the adjustable stop.

.Fig. 4 is a front elevational view of the sewing machine with the righthand portion of the work-table broken away and the bed and a portion ofthe standard in section to disclose the mechanism located within thestandard.

Fig. 5 represents an enlarged transverse vertical sectional view takensubstantially along the line 5-5, Fig. 1, showing the eccentric mountingof the work-table onthe base of the machine.

Fig. 6 represents a vertical sectional view taken transversely ofthework-table, showing a modification of the means employed for connectingthe work-table to the yieldable work-table elevating means.

Fig. 7 represents a horizontal sectional view taken substantially alongthe line 7- 7, Fig. 6.

Fig. 8 is a left hand elevation of the cable-securing clamp shown inFig. 6.

Referring to the accompanying drawings, the improved sewing machineincludes a frame comprising a base or base-arm 10 having a hollowstandard 11 rising from the rear right hand corner thereof. Extendinglaterally towards the left from the upper end of the standard is ahorizontal upper arm 12, and extending forwardly from the left hand endthereof is a frame-arm 13. Attached to the free end of the arm 13 is astationary resser-plate or foot 14 against which the work is clamped bya pair of conventional vertically yieldable work-clamping members 15carried by a work-table 16 which is supported by the base 10.

Journaled in the horizontal arm 12 is a main rotary shaft 17 which,through the usual connections disclosed for example in the U. S. patentof Dearborn, No. 705,325, July 22, 1902, oscillates a needle shaft 18which is journaled in the forwardly extending arm 13. Carried by theforward end of the needle shaft 18 is a curved needle 19 whichoscillates directly above the resser-plate 14 and in a path transverseto the longitudinal axis thereof, the forward or work-penetrating strokebeing from left to right. Cooperating with the needle in the formationof chain-stitches is a looper 2t] actuated, in the manner shown in theU. S. patent of Dearborn, No. 639,669, December 19, 1899, from the mainshaft 17. The work is fed rearwardly past the needle 19 by means of afourmotion feed-dog 21 which operates through a hole in the presser-foot14 and in opposition to the vertically yieldable work-clamping members15, all in a manner substantially like that disclosed in the U. S.patent of Dearborn No. 1,592,446, July 13, 1926.

The work to be stitched is supported on the work-table 16 which isformed at its free left hand end as a tube or horn beneath the stitchingand feeding mechanisms and at its right hand end is enlarged intosubstantially rectangular form having a convex upper surface, closed bya cover-plate 22 (Fig. 2), and a pair of depending endwalls 23 and 24.The end walls 23 and 24 are preferably fitted with bushings 25 and 26(Fig. 5) in which are journaled the reduced eccentrically locatedopposite ends 27 and 28 of a work-table supporting shaft 29 freelyjournaled in the spaced upstanding lugs 30 and 31 integral with abracket 32 detachably secured by screws 33 to the bed 10. Spring meansis employed for yieldingly urging the work-table into its normalelevated workpresenting position determined by a stop-screw 34 which isthreaded into the depending front wall 35 of the worktable 16, thestop-screw 34 at its inner end bearing against a stop-plate 36 securedby a screw 37 to an ear 38 cast on the bracket 32. Treadle or knee-shiftcontrolled means is provided for pivotally lowering the work-table 16about the eccentrically located ends 27 and 28 of the work-tablesupporting shaft 29. This means preferably includes a rock-shaft 39(Figs. 1 and 5 journaled in a bracket 40 attached to the base 10, therock-shaft 39 being bent to extend across the front of and downwardlybeneath the machine to form a knee-shift arm 41 carrying adjacent itslower end a knee-pad 42. The rockshaft 39 has secured to it a rock-arm43 connected at its inner end by a wire-link 44 to the work-table 16.Pressure applied to the knee-pad 42 causes the work-table to tiltdownwardly about its pivotal support, thus moving the tubularportion ofthe work-table away from the overlying presser-foot to release the work.

The spring means employed for yieldingly urging the work-table 16 intoits 'elevated position is arranged so that, as the work-table is loweredby manual actuation of the knee-shift, the effort required by theoperator becomes less as the work-table approaches its lowered position.'1 To that end, the means shown in Figs. 1, 2 and'3 comprises alink 45connected at one end by a screw 46 to the depending wall 35 of thework-table 16 and at its other end connected by a screw 47 to one sideof a pivotally mounted element or bell-crank lever 48 which is fulcrumedon the shouldered pivot-stud 49 threaded into the car 39. To the otherside of the bell-crank lever 48 there is attached, by a screw 50, oneend of a link 51 having its other end connected to a rather heavycoil-spring 52 which is anchored to a stud 53 endwise adjustable in themachineframe. The desired reduction in effort required as the work-tableapproaches its lowered position results from the fact that as thework-table is lowered there is a relative increase in the effectivelength of the lever-arm represented by the distance from the axis of thepivot-screw 49 to the axis of the screw 47 simultaneously with adecrease in the effective length of the lever-arm represented by thedistance from the axis of the pivot-screw 49 to the axis of the screw50. Stated more broadly, it may be said that the ratio of the effectivelever-arm lengths increases in the work-table lowering action of thekneeshaft 42, resulting in a lessening or diminishing of the effortrequired by the operator. Figs. 6, 7 and 8 illustrate a modification ofthe means for connecting the coil-spring 52 to the work-table 16. In themodification, the bellcrank 48 together with the link 45 has substitutedtherefor a drum 54 turnably mounted on the shouldered stud 49 and aboutwhich there is wound a flexible cable 55 having one end secured to thedrum 54 by the screw 56 and its other end attached to the dependingfront wall 35 of the work-table 16 by a securing screw 57 and aclamp-bar 58. It will be understod that with the parts in the positionas shown in Fig. 6, manual lowering of the work-table 16 about itspivots 27 and 28 will cause the depending front wall 35 of thework-table to swing upwardly to the left and, through the cable 55, thedrum 54 will turn in a clockwise direction causing the link 51 to moveto the left in opposition to the coil-spring 52. When the worktable isreleased, the spring 52 causes the work-table to swing back to itsnormal elevated position determined by the stop-screw 34. Themodification also has the advantage of requiring less effort as thework-table approaches its lowered position, this being the case byvirtue of the fact that the effective lever-arm represented by distanceof the center of the shouldered screw 49 to the center of the screw 50decreases relative to the radius of the drum 54 as the work-table movesto lowered position.

The work-table 16 provides supporting means for the usual ridge-former59 (Fig. 4) which functions in cooperation with the presser-foot 14 informing a bight in the material facilitating the penetration of thematerial by the curved needle 19 so as to form blind stitches. In themachine illustrated, the ridge-former 59 is actuated so that shallow orskip stitches are formed between successive deep or anchor stitches.This is automatically accomplished by periodically raising and loweringthe ridgeforming element or fin independently of the work-table. Themechanism disclosed in the drawings for effecting this rise and fall ofthe ridge-former forms the subject of another of my patent applicationsSerial No. 292,263, filed herewith and, therefore, reference may be hadto that application for a complete disclosure of that mechanism. Sufficeit to say that in the present drawings, the ridge-former 59 isillustrated as being clamped upon the left hand end portion of a tubularshaft 60 freely journaled to oscillate on the eccentrically disposedbody of a telescopically arranged skip-stitch shaft 61 supported at itsopposite ends in spaced bearings 62 provided within the work-table 16.At its right hand end, the tubular shaft has clamped on it a dependingrock-lever 63 connected by a rearwardly extending link 64 to thedepending arm 65 of a bell-crank lever freely fulcnlrned on askip-stitch pivot-stud 66 which is supported in the machine standard 11vertically beneath and in parallelism with the rotary main-shaft 17 ofthe machine. The rearwardly extending horizontal arm 67 of thebell-crank lever is connected to the lower end of a pitman 68 whoseupper end embraces an eccentric 69 fast on the main-shaft 17. Rotationof the main-shaft 17 will effect a complete oscillation of theridge-forming element 59 during each stitch-forming cycle in a directionto assist the feed-dog 21 in advancing the material through the machine.The height of the ridge-forming element 59 is normally set by manuallyadjusting, by means later to be described, the elevation of theWork-table 22 in accordance with the thickness of the material beingsewn. When the ridge-former 59 is in the forward end of its oscillatorystroke, the work is properly positioned for penetration by the needle19.

In order to form skip stitches between the anchor stitches, means isprovided for turning, to a limited extent, the eccentric bodiedskip-stitch shaft 61 within the tubular ridge-former supporting shaft60. Turning of the skip-stitch shaft 61 relative to the tubular shaft 60effects a bodily drop of the ridge-former 59 and its tubular shaftrelative to the needle 19 so that the latter, in penetrating the work,passes through less than the total plies of material folded over theridge-former 59 The means for turning or oscillating the skip-stitchshaft 61 comprises a rock-lever 70 clamped upon the right hand end ofthe skip-stitch shaft 61 and having its lower end connected by arearwardly extending pitman 71 embracing an eccentric 72 which issecured on a belt driven sprocket 73 journaled on the skip-stitchpivot-spindle 66. The sprocket 73 is driven by a clip-belt 74 from abelt sprocket 75 on the arm-shaft 17, the ratio of the belt-sprockets 73and 75 illustrated in the drawings being such that the main-shaft 17makes two revolutions for each revolution of the skipstitch eccentric72. It will be apparent that the ratio between the main-shaft and theeccentric 72 on the skip! stitch pivot-spindle may also be of the orderof 3-to-1 or 4-to-1.

Referring again to the work-table 16, means are provided for adjustingthe height thereof to regulate the depth of penetration of theblind-stitch. This means, best shown in Fig. 2, is capable of micrometeradjustment and includes a manually controlled element, the actuation ofwhich turns the work-table supporting shaft 29 which, owing to theeccentrically disposed ends 27 and 28 thereof, results in bodilyelevating or lowering the work-table relative to the stitchingmechanism. The manually controlled work-table height adjusting meanscomprises a rock-lever 76 clamped on the work-table supporting shaft 29and having connected thereto one end of a rearwardly extending link 77which is connected at its other end to the lower end of a verticallydisposed adjusting lever 78 fulcrumed intermediate its ends on apivot-stud 79 fixed in a lug 79' preferably cast integral with one wallof the machine-standard 11. At its upper end, the adjusting lever 78 isformed as a yoke 80 of which the parallel limbs are slotted, as at 81,to receive the side pins 82 of a block 83 which is threaded upon anadjusting screw 84., The adjusting screw 84 is formed with a cylindricalbody-portion 85 rotatably disposed in an extended part 86 of adetachable cover-plate 87, the adjusting screw 84 being constrainedagainst endwise movement in the coverplate by a flange 88 and a thumbdisk 89 secured by a screw 90 to the squared end 91 of the screw 84.Indicia scribed in the peripheral face of the thumb disk 89 facilitatesthe accurate adjustment of the normal elevated position of thework-table 16. From the above, it will be understood that manual turningof the thumbdisk 89 causes the block 83 to travel along the adjustingscrew 84, whereby the connections 76, 77 and 78 are actuated to turn thework-table supporting shaft 29 in its bearings 30 and 31, causing theeccentrically disposed ends 27 and 28 of the work-table supporting shaftbodily to elevate or lower the work-table 16. It will be obvious that byjournaling the adjusting screw 84 in the detachable cover-plate 87 andby forming the upper end of the adjusting lever 78 as a yoke, thedetachable cover-plate 87 can be readily removed from the machine andwhen so done all the mechanism within the standard 11 is convenientlyaccessible for replacement or adjustment. The bed at the top is alsoclosed by a cover-plate 92, the removal of which gives access to themechanism within the bed. It will be appreciated that with thecover-plates 87 and 92 being located as shown in Fig. 2, they may beremoved without having to drain all the oil from the bed 10. Moreover,it will be appreciated that the cover-plates 87 and 92 are constructedand arranged and are of such a size that all the mechanism within thebase-arm 10 and standard 11 is exposed when the plates are removed.Also, in the initial assembly of the machine, or during adjustment orrepair, with the cover-plates removed the machine may be operated, andthe action of the mechanism within the base-arm and standard observedduring its operation. While I have shown cover-plates 87 and 92 to bemade separate, it will be obvious that a single L-shaped cover-platecould be utilized to close both the base 10 and standard 11.

To provide for increasing the work-supporting surface of the work-table16 when the machine is to be used for fiat work there is a swing-outplate 93 supported to swing about a vertical pivot 94 provided on anupwardly curved bracket 93 sustained by the machine-bed. A wing-nut 96and stud 97 depending from the swing-out plate 93 and cooperating withan openended slot 98 in the bracket 95 provide locking means forfastening the swing-out plate in operating position in the horizontalplane of the top of the tubular worktable 16.

Having thus set forth the nature of the invention, what I claim hereinis:

1. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm section extendingforwardly from said standard and cooperating with the latter to supportthe frame; a work-table section movably mounted on said base-arm andhaving a portion disposed at a level below the free end of saidforwardly extending frame-arm; a work-table supporting shaft mounted insaid work-table and journaled for limited turning movement on saidbase-arm and providing the support about which said work-table moves,said worktable supporting shaft having at least one eccentricallydisposed portion with which one of said sections is in bearing contact;and work-table supporting shaft turning connections operativelyassociated with said worktable supporting shaft for effecting limitedturning of said shaft to move said work-table section upwardly ordownwardly relative to said frame-arm.

2. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm extending forwardly fromsaid standard and cooperating with the latter to support the frame; awork-table mounted on said basearm and having a portion disposed belowthe level of the free end of said forwardly extending frame-arm; andmeans for mounting said work-table on said basearm including awork-table supporting shaft mounted for limited turning movement on saidbase-arm, at least one eccentrically disposed section formed on saidworktable supporting shaft and on which said work-table is journaled,and manually actuated work-table supporting shaft turning connectionsoperatively associated with said work-table supporting shaft foreffecting limited turning of said shaft to move said work-table upwardlyor downwardly relative to said frame-arm.

3. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm section extendingforwardly from said standard and cooperating with the latter to supportthe frame; a work-table movably supported on said base-arm and having aportion disposed below the level of the free end of said forwardlyextending frame-arm; eccentric means located at the point of support ofsaid work-table on said base-arm and providing a bearing support onwhich said work-table is journaled; and manually controlled connectionsoperatively connected to said eccentric means for rotating the latterand thereby effecting a movement of said work-table relative to saidbase-arm.

4. Ina blind-stitch sewing machine, a main frame including a standardhaving an uper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm section extendingforwardly from said standard and cooperating with the latter to supportthe frame; a work-table mounted on said basearm and having a portiondisposed below the level of the free end of said forwardly extendingframe-arm; a worktable supporting shaft journaled in said base-arm andhaving formed thereon spaced eccentrically disposed portions on whichsaid work-table is journaled; manually actuated work-table supportingshaft turning connections operatively associated with said work-tablesupporting shaft for effecting limited turning of said shaft thereby toregulate the normal working position of said work-table; and means forturning said work-table about the axis of the eccentrically disposedportions of said work-table supporting shaft to move said work-tabletoward and away from said frame-arm.

5. In a blind-stitch sewing machine; a main frame including an opensided standard having an upper arm extending laterally therefrom andterminating in a forwardly extending frame-arm, a base-arm sectionextending forwardly from said standard and cooperating with the latterto support the frame, and a cover-plate detachably secured to saidstandard to close its open side; a work-table section movably mounted onsaid base-arm and having a portion disposed at a level below the freeend of said forwardly extending frame-arm; a work-table supporting shaftmounted in said work-table and jour-' naled for limited turning movementon said base-arm and providing the support about which said work-tablemoves, said work-table supporting shaft having at least oneeccentrically disposed portion on which one of said sections isjournaled; and work-table supporting shaft turning connectionsoperatively associated with said worktable supporting shaft foreffecting limited turning of said shaft to move said work-table sectionupwardly or downwardly relative to said frame-arm, said work-table supporting shaft turning connections including a manually actuable membercarried on said cover-plate and separably associated with the remainingshaft turning connections so that the cover-plate and the manuallyactuable member can be readily removed from said standard.

6. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm section extendingforwardly from said standard and cooperating with the latter to supportthe frame; a work-table section movably mounted on said base-arm andhaving a portion disposed at a level below the freeend of said forwardlyextending framearm; a work-table supporting shaft mounted in saidworktable and journaled for limited turning movement on said base-armand providing the support about which said work-table moves, saidwork-table supporting shaft having at least one eccentrically disposedportion with which one of said sections is in bearing contact; andwork-table supporting shaft turning connections operatively associatedwith said work-table supporting shaft for effecting limited turning ofsaid shaft to move said work-table section upwardly or downwardlyrelative to said framearm, said work-table supporting shaft turningconnections including a rock-lever fixed on said Work-table supportingshaft, an adjusting lever disposed in said standard, a link connectingsaid adjusting. lever to said rock-lever, and a manually actuable membermounted for movement on said main frame and operatively connected tosaid adjusting lever whereby movement of said member Will effect anadjustment of the working position of said worktable.

7. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm extending forwardly fromthe lower portion of said standard; a supporting. shaft journaled forturning movement in said base-arm, said shaft having at least oneeccentrically disposed portion; a work-table journaled on saideccentrically disposed shaft-portion and having its free end disposedbelow the level ofv the free end of said frame-arm; a rock-arm securedto said supporting shaft; an adjusting lever pivotally mounted on saidmain frame and operatively connected to said rock-lever; and a thumbdisk rot'atably supported on said main-frame and connected to saidadjusting lever.

8. In a blind-stitch sewing machine, a main frame including a hollowopen-sided standard having an upper arm extending laterally therefromand terminating in a forwardly extending frame-arm, a box-like base-armextending forwardly from said standard and having an open top;stitch-forming and Work-feeding mechanisms provided in said frame-arm; awork-table movably mounted on said base-arm and having its free enddisposed below the: free end of said frame-arm; a ridge-former carriedby said work-table; ridge-former actuating mechanism disposed withinsaid box-like base-arm and said hollow standard; and cover-platesclosing the open top of said base-arm and the open side of said hollowstandard, said cover-plates being constructed and arranged and of suchsize that when they are removed all the mechanism within the base-armand standard is exposed for convenient adjustment or replacement.

9. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm extending forwardly fromsaid standard; a Work-table movably mounted on said base-arm and havinga portion disposed at a level below the. free end of said forwardlyextending frame-arm; adjustable stop means for positioning saidwork-table. in its normal elevated position relative to said. frame-arm;manually operable work-table lowering connections for moving saidwork-table away from said frame-arm; and yieldable connections forreturning said work-table to its normal elevated position relative tosaid frame-arm, said yieldable connections including a. spring and alinkage having a pivotally mounted element and a pair of links connectedto said pivotally mounted element, said pivotally mounted elementproviding with, saidlinks a pair of lever-arms of which the ratio of theeffective lengths thereof changes during the work-table lowering actionof the manually operable work-table lowering connectionsin a manner todecrease the effort required to be expended. by the operator in movingthe work-table away from the frame-arm.

10. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base arm extending forwardly fromsaid standard; a work-table movably mounted on said base-arm and havinga portion disposed at a level below the free end of said forwardlyextending frame-arm; adjustable stop means for positioning saidwork-table in its normal elevated position relative to said frame-arm;manually operable work-table lowering connections for moving saidwork-table away from said frame-arm; and yieldable connections forreturning said Work-table to its normal elevated position relative tosaid frame-arm; said yieldable connections including a pivotally mountedelement, a member connecting said pivotally mounted element to saidwork-table, a second member connected to said pivotally mounted element,and a spring connected at one end to said second member and at its otherend to said main-frame.

11. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm extending forwardly fromsaid standard; a work-table movably mounted on said base-arm and havinga portion disposed at a level below the free end of said forwardlyextending frame-arm; adjustable stop means for positioning saidwork-table in its normal elevated position relative to said frame-arm;manually operable work-table lowering connections for moving saidWork-table away from said frame-arm; and yieldable connections forreturning said work-table to its normal elevated position relative tosaid frame-arm; said yieldable connections including a pivotally mountedelement, a link connecting said pivotally mounted element to saidwork-table, a second link also connected to said pivotally mountedelement, and a spring connecting said second link to said main frame.

12. In a blind-stitch sewing machine, a main frame including a standardhaving an upper arm extending laterally therefrom and terminating in aforwardly extending frame-arm, and a base-arm extending forwardly fromsaid standard; a work-table movably mounted on said base-arm and havinga portion disposed at a level below the free end of said forwardlyextending frame-arm; adjustable stop means for positioning saidwork-table in its normal elevated posit-ion relative to said frame-arm;manually operable work-table lowering connections for moving saidwork-table away from said frame-arm; and yieldable connections forreturning said work-table to its normal elevated position relative tosaid frame-arm; said yieldable connections including a. drum rotatablymounted on said main frame, a flexible cable wound about said drum andconnected at itsgfree end to said work-table, a link connected at oneend to said drum, and a spring connected at one end to said link and atits other end to said. main frame.

References Cited in the file of this patent UNITED STATES PATENTS2,175,966 Moulton et al. Oct. 10, 1939 2,188,229 Mueller Jan. 23, 19392,194,149 Mueller Mar. 19, 1940

